The present invention is generally directed to steering of a farm implement and, more particularly, to a method for controlling an implement steering system.
Many tillage, seeding, and planting equipment are designed to be drawn behind tractors and the like. Most of these towed devices are steered primarily by the tractor and do not have their own steering mechanisms.
Increasingly however, farm implements and other towed devices are being equipped with steering systems that allow the towed device to steer independent of the towing device, e.g., tractor. Seeding implements, for example, equipped with implement steering systems, allow the seeding implement to remain aligned with the tractor at all times during seeding in order to obtain straight and even seed rows. However, when the tractor is traversing in a direction perpendicular to the slope of the land, the implement steering system allows the seeding implement to move independently of the tractor to avoid the implement from “side slipping” or moving in the direction of the slope thereby falling out of alignment with the tractor. In this regard, the implement steering system provides for consistent row spacing.
Another circumstance when it is desirable to have an independently steerable implement is when the tractor must maneuver the implement around an obstruction such as a slough, telephone pole, large boulder and the like. If the towed implement does not have independent steering, the tow vehicle must make a wider turn which will result in a tendency for the towed implement to “cut corners” thereby, in the case of a seeding implement, the seed openers are more apt to twist instead of travel straight ahead, which is the intended use.
Thus, a towed implement having independent steering would be able to steer itself back into alignment with the tractor and minimize the towed vehicle's arc of travel. This can be accomplished by equipping the towed implements with at least one steerable surface engaging wheel, and more preferably, with two steerable surface engaging wheels integrated as part of the main frame of the towed implement. Steering can either be automatically controlled by means of a steering angle sensor, global positioning sensor (GPS) or could be operator controlled.
One of the drawbacks of conventional implement steering systems is that the system, once activated, remains activated until it is manually deactivated. This can be problematic if the implement steering system is engaged when conditions are not well-suited for auto-steering. For example, most implement steering systems are designed for use at lower speeds, such as the speeds during field operation. When the implement is being transported, which is typically done at higher travel speeds, conventional implement steering systems do not have the response time that is necessary to make timely corrections to the implement's position, thus are typically disabled.
The present invention provides an implement steering system that self-disables if a high travel speed is detected. Once the implement has returned to a safe auto-steering speed, the implement steering system is automatically enabled. In this regard, the invention does not require manual shut-off of the implement steering system at higher travel speeds. Similarly, the invention does not require an operator to manually enable the implement steering system when safe operating speeds are obtained.
The present invention also provides for auto-centering of the steering system when in transport. As implements become larger, navigation around turns becomes increasingly difficult. Having an independent steering system provides needed assistance for negotiating turns. This also requires the operator's attention when negotiating back out of the turn. In some cases this leads to operator distraction. The present invention provides an auto-center feature that allows the steering system to self-align when a target ground speed is detected in the event the operator becomes distracted with forward operation.
The implement steering system of the invention is designed to remain relatively quiet when the implement is being towed during in-field use, i.e., during active seeding. Although relatively quiet as the implement is being towed along rows, the implement steering system of the present invention is designed to independently auto-center the steering system of the implement at headland turns to correct for field impacts, internal leaks, thermal changes and other conditions that may have caused misalignment of the implement. In this regard, the implement steering system has a self-centering feature that is active during headland turns and at other turning instances.
In addition to accounting for unsafe auto-steering conditions, the present invention also provides an implement steering system that is selectively enabled and disabled based on the mode of operation of the implement.
It is an object of the invention to provide an implement steering system that is disabled automatically at higher transport speeds.
It is also object of the invention to provide an implement steering system that automatically centers itself relative to the defined calibration value at headland turns of the towing vehicle.
It is another object of the invention to provide an implement steering system that automatically disables itself if a steering angle of the implement is outside an acceptable range of values.
It is yet a further object of the invention to provide audio and/or visual indications to an operator conveying the status of the implement steering system for the implement.
Other objects, features, aspects, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.